In order for the animal and human body to function properly, it must be exercised, or as derived from the Latin root word, exarcere, it must be "let out" -- involved in movement. It is benefical to the body if such movement requires both conscious and reflex effort to be put forth by the person or animal. It is much more benefical if all systems of the body including muscular, cardiovascular, pulmonary, blood, and other systems involving balance, eye and brain are totally involved in rhythmic movements such as walking, jogging, running and other rhythmic body movements. These movements require the expenditure of gradually increasing energy or effort to facilitate hemo-oxygen exchange throughout the body, strengthen muscles and blood vessels, stimulate body organ functions and electrical and chemical actions and secretions. Also, it is more beneficial if these movements can be accomplished in an alternating compression-tension muscular action without a hammering or jarring effect on the various body parts or the total body.
Greater muscular effort and a higher energy output is required on terrain other than flat hard surfaces. Surfaces such as turf, mud, sand, deep sand, downhill, uphill, and uneven ground require greater exertion due to the shifting of the center of gravity of the body and the consequent muscular action necessary to maintain body balance. Not only are more effect and energy required, but more agility, flexibility, isometric and isotonic muscle action, and body-eye-brain coordination. The changing terrain causes the body to react with muscle actions and counter actions requiring more muscular effort, therefore more body benefits are derived in a shorter period of time than on a flat surface. A flat hard surface does not require the expenditure of a comparable effort since the body center of gravity is not moved any significant distance when running in place. Therefore, an uneven resilient surface and one that is capable of changing contour is desirable. This simulation of various types of terrain not only requires greater conscious and reflex effort in the rhythmic style but it is less monotonous and it generates more interest in exercising than a flat surface.
A review of patent documentation indicates that a few attempts have been made to provide resilient yielding surfaces with a change of resistance. However, the present invention provides resilient yielding surfaces and includes the capability of changing the surface characteristics and resistance, at will, to simulate changing terrain while the body is being exercised in a manner utilizing natural body movements and motions when simulating running, jogging, walking, balancing and other body movements and motions.